As a fixed contact and a movable contact of a relay, a switch, or the like, rivet-type contacts have been conventionally used. The rivet-type contacts are made of a head part that acts as an electric contact, and a leg part that is deformed by caulking when being fixed to various devices. Then, at fixation of the rivet-type contact, the leg part of the rivet-type contact is inserted into a hole drilled in a base in advance, and is pressed with a caulking tool from a back side (leg part side). With the caulking processing, the diameter of the leg part is increased and the leg part is closely attached to a wall surface of the hole, and the diameter of an end part of the leg part becomes larger than that of the hole, so that the fixation is made.
In the past, the entire rivet-type contact has been configured from a contact material. However, an Ag alloy or the like, which is the contact material, is expensive. Therefore, to decrease the material cost, a two-layer rivet-type contact has been typically used, in which the contact material is partially applied, and a relatively low cost material (base material) such as copper or a copper alloy is applied to other parts.
As a configuration of the two-layer rivet-type contact, one in which the head part is formed into a two-layer structure, an upper surface part of the head part is configured from the contact material, and a lower surface part of the head part and the leg part are made of the base material such as Cu is known, for example (FIG. 7(a), see Patent Document 1). In a process of manufacturing the two-layer rivet-type contact, first, a columnar contact material and a base material are pressure-welded and integrated, preliminary processing and molding processing are performed, and a two-layer structure made of a head part and a leg part is formed.
Further, as the two-layer rivet-type contact, there are one in which the above-described head part is formed into a two-layer structure, and one in which the entire head part is configured from the contact material and the leg part is configured from the base material (FIG. 7(b), see Patent Document 2). These types of two-layer rivet-type contacts are manufactured such that a columnar leg part (base material) is brazed to a disk head part (contact material).